The organizers of the decade-long, Google-sponsored Lunar XPrize contest quietly ended it this week without a $20 million winner.

The Lunar X competition was first announced in 2007 and boasted a $20 million grand prize to the first team that could successfully land a private spacecraft on the Moon.

The latest deadline for a rocket launch for the five finalists was March 31, 2018 – but according to a statement from the organizers, none of the teams believed they would hit the deadline, which had already been extended multiple times over the years.

“After close consultation with our five finalist Google Lunar XPRIZE teams over the past several months, we have concluded that no team will make a launch attempt to reach the Moon by the March 31st, 2018 deadline. This literal ‘moonshot’ is hard, and while we did expect a winner by now, due to the difficulties of fundraising, technical and regulatory challenges, the grand prize of the $20M Google Lunar XPRIZE will go unclaimed,” wrote Peter H. Diamandis, founder and executive chairman of XPRIZE, and Marcus Shingles, chief executive officer of XPRIZE.

The Lunar XPrize competition launched in 2008 as a follow-up to the first Ansari X Prize, which challenged teams to produce the first privately-funded spacecraft capable of making it into space. SpaceShipOne, designed by Scaled Composites, took the prize in that competition in 2004.

Lunar XPrize was financed by Google and initially had more than 25 participating teams. Ultimately, the five finalists were Moon Express, representing the U.S.; SpaceIL, of Israel; Team Hakuto, of Japan; Team Indus, of India; and Synergy Moon, an international team.

If a winner had been declared, a $20 million prize would have been earned by the team that landed a robotic rover on the surface of the Moon and had it travel at least 1,640 feet (500 meters). Requirements for the prize also included sending high-definition videos and photos back to Earth as proof. The second place team would have received $5 million. However, more than $6 million was dispersed to teams throughout the contest that reached specific milestones and completed smaller-scale challenges.

Despite not being able to announce a winner, the competition was still a success in the organizers’ eyes, and sparked a conversation regarding who can land on the Moon, they wrote. Landing on the Moon and exploring space is no longer limited to a select group of government agencies, according to the organizers.

Six additional outcomes were listed by the organizers that they believe also contributed to the competition’s success. For example, the first commercial space companies in India, Malaysia, Israel and Hungary were established and more than $300 million was raised by the teams, including the largest space-related series A investment of $90 million.

One of the finalists, Moon Express, received the first-ever “Mission Approval” from the U.S. government to send a private spacecraft beyond Earth’s orbit and to the Moon.

The organizers also believe the wide-spread media exposure led to increased interest in STEM fields among thousands of people across the globe.

“In conclusion, it’s incredibly difficult to land on the Moon. If every XPRIZE competition we launch has a winner, we are not being audacious enough, and we will continue to launch competitions that are literal or figurative moonshots, pushing the boundaries of what’s possible,” said Diamandis and Shingles.